Releasing method and releasing apparatus of work having adhesive tape

ABSTRACT

In a method for releasing a work having an adhesive tape from a holding member which sucks and holds the work having the adhesive tape, the work having the adhesive tape is released from the holding member while supplying a gas which reduces a holding force of the holding member between the holding member and the work having the adhesive tape.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to a releasing method and a releasingapparatus of a work having an adhesive tape for releasing the workhaving the adhesive tape from a holding member which sucks and holds thework having the adhesive tape after it is subjected to a predeterminedprocessing.

(2) Description of the Related Art

Conventionally, a surface protecting tape is joined to a surface of asemiconductor wafer formed with a pattern. The surface protecting tapeprotruding from an outer periphery of the semiconductor wafer is cut outalong an outer peripheral edge of the semiconductor wafer, a backsurface of the semiconductor wafer is polished in a state in which theentire semiconductor wafer surface is protected by the surfaceprotecting tape, and the semiconductor wafer is thinned (see JP-A6-302569, for example).

A protecting tape (dicing adhesive tape) is joined (wafer mount) to thesemiconductor wafer whose back surface has been polished for cutting thewater into chips (dicing). Then, in order to separate the surfaceprotecting tape from the semiconductor wafer, the wafer is subjected toa so-called mount separating processing (see JP-A 2003-209082, forexample). Since the semiconductor wafer is thin, it is general that themount separating processing is carried out in a state in which a widerange of a back surface of the dicing adhesive tape is sucked and heldon the holding member made of a porous material.

If the back surface of the dicing adhesive tape is sucked and held onthe holding member made of a porous material, a delay of release isgenerated in a holding region is generated at the time of releasing, andthere is a problem that the dicing adhesive tape is deformed and thesemiconductor wafer is cracked or damaged.

In the mount separating processing, in order to facilitate theseparation of the surface protecting tape, a heated holding member isused. Therefore, the dicing adhesive tape is deformed more and thus, thedicing adhesive tape is prone to enter into a sucking hole of theholding member, and the semiconductor wafer becomes prone to be damaged.

SUMMARY OF THE INVENTION

The present invention is made in view of the above circumstances, and itis therefore an object of the present invention to provide a releasingmethod and a releasing apparatus of a work having an adhesive tape forpreventing a work such as a semiconductor wafer from being damaged whena back surface polishing process is completed, after a dicing adhesivetape surface joined to cut the wafer into chips (dicing) is mounted andheld on the holding member which sucks and holds the dicing adhesivetape surface, the semiconductor wafer, i.e., a work having an adhesivetape to which the dicing adhesive tape is joined after a so-called mountseparating processing to separate the surface protecting tape of thesemiconductor wafer surface is carried out is released from the holdingmember which sucks and holds the adhesive tape.

In order to achieve the above object, the present invention has thefollowing configuration:

A method for releasing a work having an adhesive tape from a holdingmember which sucks and holds the work having the adhesive tape, themethod comprising the step of:

releasing the work having the adhesive tape from the holding memberwhile supplying a gas which reduces a holding force of the holdingmember between the holding member and the work having the adhesive tape.

According to the releasing method of the present invention, by supplyingthe gas such that the holding force of the holding member is reduced, itis possible to reliably take out the adhesive tape entering into thesucking hole of the holding member, and to eliminate the residualpressure between the adhesive tape and the holding member. Further,since it becomes easy to release the work, it is possible to suppressthe crack or damage of the work having the adhesive tape which is anarticle such as a semiconductor wafer or lead frame.

In the releasing method of the present invention, preferably, the gas issupplied to the entire region where the work having the adhesive tape isheld between the work having the adhesive tape and the holding member.

According to the releasing method of the present invention, by supplyingthe gas to the entire region where the work having the adhesive tape isheld, it is possible to reliably release the work having the adhesivetape.

In the releasing method of the present invention, preferably, the gas issupplied in sequence from a central portion to an outer side of theholding member.

According to the releasing method of the present invention, by supplyingthe gas in sequence from the central portion to the outer side of theholding member, it is possible to smoothly release the work having theadhesive tape, and to reliably prevent the work from being damaged.

In the releasing method of the present invention, preferably, the gas issupplied to the work having the adhesive tape in a vacuum sucked state.

According to the releasing method of the present invention, since thegas is supplied to the work having the adhesive tape in a vacuum suckedstate, it is possible to adjust the holding force by the vacuum suction.With this, it becomes possible to adjust the holding force by the vacuumsuction depending upon the kinds of the adhesive tape, and it ispossible to prevent the adhesive tape from being deformed when it isvacuum sucked.

In the releasing method of the present invention, preferably, the gas issupplied from two or more gas supply openings.

According to the releasing method of the present invention, since thegas is supplied from the two or more gas supply openings, it is possibleto form a gas flow in addition to gas which adjusts the holding force ofthe vacuum suction. Therefore, when the work having the adhesive tape isto be released, it is possible to release the work having the adhesivetape while moderating a stress applied to the work.

An example of the work having the adhesive tape is an adhesive tapewhose back surface is joined to the ring frame and the semiconductorwafer to integrally form the ring frame and the semiconductor wafer.

In order to achieve the above object, the present invention also has thefollowing configuration:

An apparatus for releasing a work having an adhesive tape from a holdingmember which sucks and holds the work having the adhesive tape, theapparatus comprising:

a holding table having a holding member for mounting and holding thework having the adhesive tape;

holding means, provided on the holding table, for sucking and holdingthe work having the adhesive tape; and

gas supply means for supplying a gas between the holding member and thework having the adhesive tape.

According to the releasing apparatus of the present invention, it ispossible to reliably take out the adhesive tape entering into thesucking hole of the holding member from the sucking hole, and toeliminate the residual pressure between the adhesive tape and theholding member. Further, the releasing process can be carried out with aseries of operations, it becomes easy to release and thus, it ispossible to suppress the crack and damage of the article and work havingthe adhesive tape such as a semiconductor wafer.

The releasing apparatus of the present invention further comprises: acontrol section which switches over the suction and holding of the workhaving the adhesive tape by the holding means and the supply of gasbetween the holding member and the work having the adhesive tape by thegas supply means.

With this structure, it becomes easy to adjust the holding force by thesuction of the work having the adhesive tape on the holding table.

For example, the holding table may commonly use the discharging flowpath for sucking the work having the adhesive tape by the holding means,and the flow path for supplying the gas by the gas supply means.Further, the holding table may separately include the discharging flowpath for sucking the work having the adhesive tape by the holding means,and the flow path for supplying the gas by the gas supply means.

In the releasing apparatus of the present invention, preferably, theholding member is made of a porous material.

If the holding member is made of a porous material, it becomes easy toprovide the sucking means for sucking the work having the adhesive tape.Further, since the gas can be supplied through the porous material, thegas can easily be supplied between the work having the adhesive tape andthe holding member.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, there are shown in thedrawings several forms which are presently preferred, it beingunderstood, however, that the invention is not limited to the precisearrangement and instrumentalities shown.

FIG. 1 is a schematic perspective view of an essential portion of oneexample of a semiconductor wafer mount apparatus having one example ofan embodiment of a releasing apparatus of a work having an adhesive tapeaccording to the present invention; and

FIG. 2 is a schematic sectional view showing an essential portion of oneexample of the releasing apparatus of the work having the adhesive tapeaccording to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An example of embodiments of the present invention will be explainedwith reference to the drawings.

FIG. 1 is a schematic perspective view showing an essential portion ofone example of a semiconductor wafer mount apparatus having one exampleof embodiments of a releasing apparatus of a work having an adhesivetape according to the present invention.

As shown in FIG. 1, a semiconductor wafer mount apparatus 1 of theembodiment includes a wafer supply section 2 to which a cassette. Aplurality of layers of semiconductor wafers (wafers, hereinafter) Wsubjected to the back grind process are accommodated in the cassette.The semiconductor wafer mount apparatus 1 also includes a wafertransport mechanism 3 having a robot arm which bends and turns, a waferpressing mechanism 4 which corrects a warped wafer into a flat surface,an alignment stage 5 which carries out the positioning, an ultravioletrays irradiation unit 6 for irradiating the surface protecting tape withultraviolet rays, a wafer chuck table 7 for sucking and holding thewafer W, a ring frame supply section 9 into which a ring frame 8 isloaded, a ring frame transport mechanism 10 for transporting the ringframe 8, a dicing tape supplying section 12 for supplying a dicing tape11, a dicing tape joining unit 13 for joining the dicing tape 11, adicing tape cut section 14 for cutting the dicing tape 11, a dicing tapecollecting section 15 for collecting the dicing tape 11 after it is cut,a ring frame vertically moving mechanism 16 which vertically moves thering frame 8 to which the dicing tape 11 is joined, a wafer mountmechanism 17 for joining the wafer W to the dicing tape 11 which isjoined to the ring frame 8, a wafer mount frame transport mechanism 18for transporting the wafer mount frame, a separating table 19 whichsucks and holds the wafer mount frame constituting the releasingapparatus to separate the surface protecting tape 20, a separating tapejoining unit 22 for joining the separating tape 21 to the wafer W whichis mounted on the separating table 19, a separating tape separating unit23 for separating the joined separating tape 21, a tape collectingsection 24 for winding and collecting the separated and processedseparating tape, a wafer mount frame accommodating mechanism 25 foraccommodating the wafer mount frame, and a wafer mount frame collectingsection 26 to which a cassette is mounted. A plurality of layers ofprocessed wafer mount frames are accommodated in the cassette.

The wafer supply section 2 inserts wafers W in their horizontal attitudewith their surfaces on which the protecting tapes are joined, into thecassette and accommodates therein in a state in which an appropriategaps are maintained between the wafers in the vertical direction, andload the cassette into the cassette stage. The wafer mount framecollecting section 26 also inserts the ring frame 8 to which the wafersW from which protecting tapes are separated are mounted, into the ringframe cassette in a state in which an appropriate gaps are maintainedbetween the wafers in the vertical direction, and accommodates the sameand loads the ring frame 8 into the cassette stage.

The robot arm of the wafer transport mechanism 3 can horizontally moveforward and backward and turn. The wafer transport mechanism 3 takes outthe wafer W from the wafer supply section 2 and supplies the wafer W tothe alignment stage 5.

When the wafer W supplied to the alignment stage 5 is warped and can notbe vacuum sucked and held, the wafer pressing mechanism 4 presses thewafer W from its upper surface to correct the warped surface into a flatsurface so that the alignment stage 5 can suck and hold the wafer W.

The alignment stage 5 carries out the positioning of the wafer W basedon an orientation flat of the wafer W or detection of a notch. When thesurface protecting tape 20 joined to the wafer surface is ultravioletrays-hardening type adhesive tape, the ultraviolet rays irradiation unitdisposed above the alignment stage 5 irradiates the adhesive tape withultraviolet rays.

Then, the wafer W is sent to or received from the wafer chuck table 7 bymeans of the alignment stage 5 while keeping the corrected flat surfaceof the wafer W.

The ring frame supply section 9 accommodates the ring frames 8 which arepositioned in a constant direction and which are laminated on oneanother. The ring frame transport mechanism 18 transports the ring frame8 while vacuum sucking and holding the ring frame 8.

The dicing tape supplying section 12 guides the dicing tape 11 taken outfrom a whole tape roll to the dicing tape joining unit 13 and the dicingtape collecting section 15 through a lower portion of the ring frame 8.The dicing tape 11 is wider than a diameter of the ring frame 8.

The dicing tape joining unit 13 joins the dicing tape 11 to the ringframe 8 and then, cuts the dicing tape on the ring frame by means of thedicing tape cut section 14. The dicing tape collecting section 15collects the dicing tape 11 after it is cut.

The ring frame vertically moving mechanism 16 vertically moves the ringframe 8 to which the dicing tape 11 is joined. A back surface of thewafer W is joined to the ring frame 8 to which the dicing tape 11 isjoined to carry out the wafer mount.

The wafer mount frame transport mechanism 18 vacuum sucks and holds thewafer mount frame 29 and transports the same.

As shown in FIG. 2, the separating table 19 constituting the releasingapparatus includes a holding table 31 having a holding member 30 onwhich a wafer mount frame 29 is mounted and held. The wafer mount frame29 comprises the ring frame 8 to which the dicing tape 11 as the workhaving the adhesive tape is joined. The separating table 19 alsocomprises holding means 32 which is provided on the holding table 31 andwhich sucks and holds the wafer mount frame 29, and gas supply means 33for supplying a gas between the holding member 30 and the wafer mountframe 29.

The holding member 30 is smaller than the work having the adhesive tape(wafer mount frame 29) so that the holding member 30 can suck and holdthe work having the adhesive tape. The holding member 30 is made of aporous material such as an inorganic material, e.g., aluminum oxide, andis disposed in the holding table 31. The holding means 32 capable ofsucking and holding the wafer mount frame 29 through the holding member30, and the gas supply means 33 for supplying the gas between theholding member 30 and the wafer mount frame 29 are continuously providedon the holding table 31.

The holding means 32 comprises a passage 28 formed in the holding table31 for discharging and supplying a gas, a discharging pipe 37 connectedto the passage 28, a pressure gage 36 for measuring a pressure in thepassage 28 formed in the holding table 31, and pressure adjusting means35 such as a solenoid valve provided between the pressure gage 36 andvacuum discharging means 34 such as a vacuum pump. The pressureadjusting means 35 is opened and closed by a signal from a controlsection 38, and adjusts the pressure in the passage 28.

The gas supply means 33 for supplying a gas between the wafer mountframe 29 and the holding member 30 comprises a supply pipe 43 connectedto the passage 28 formed in the holding table 31, pressure adjustingmeans 40 such as a solenoid valve connected to the supply pipe 43, aflowmeter 41, and a pressure gage 42. The pressure adjusting means 40 isconnected to the control section 38 and is opened and closed by a signalfrom a pressure of the pressure gage 36 provided in the discharging pipe37, thereby adjusting the pressure. Although only one passage 28 isprovided in the holding table 31 for supplying and discharging a gas inFIG. 2, a passage 28 for supplying the gas and another passage 28 fordischarging the gas may separately be provided.

These passages 28 are branched substantially in the entire region of thework having the adhesive tape (wafer mount frame 29) in the holdingtable 31, but they may be branched outside the holding table 31. It ispreferable that each of the branched passage is provided with a valvewhich is opened and closed by a signal from the control section 38. Withthis structure, it is possible to reliably supply and discharge the gasfrom the central portion of the holding member to outside in sequence.

Other than branching the gas passage 28 inside or outside of the holdingtable 31 as described above, if two or more gas supply openings 44 whichare connection between the supply pipe 43 and the passage 28 are formed,and passages connected to the gas supply openings 44 are formed in theholding table 31, it is possible to adjust the holding force of theholding member 30 more reliably.

The gas to be supplied by the supply means 33 is not limited, and anygas may be used only if it can deteriorate the adhesion between theholding member 30 and the work having the adhesive tape. Examples of thegas are compressed air, nitrogen gas and argon gas.

As shown in FIG. 1, the separating table 19 vacuum sucks and holds thewafer mount frame 29, and the separating tape 21 is joined to thesurface protecting tape 20 on the wafer W by the separating tape joiningunit 22. The tape separating unit 22 separates the joined separatingtape 21 and the surface protecting tape 20 integrally. The tapecollecting section 24 collects the separated and processed separatingtape 21. When the surface protecting tape 20 is to be separated, thewafer mount frame 29 is heated by a heater 39 (see FIG. 2) provided inthe holding table 31 so that the surface protecting tape 20 can easilybe separated. At that time, since the dicing tape 11 is also heated, thedicing tape 11 is prone to be softened and deformed, and the dicing tape11 can easily enter the hole of the holding member 30. In the presentembodiment, however, the gas is supplied between the holding member 30and the dicing tape 11 to expel the dicing tape 11 entering into thehole of the holding member 30 toward the surface of the holding member30, and the wafer mount frame 29 can easily be released.

The wafer mount frame accommodating mechanism 25 vacuum sucks and holdsthe wafer mount frame and transports the same, and prepares toaccommodate the wafer mount frame into the wafer mount frame collectingsection 26.

Next, a basic procedure of the semiconductor wafer mount apparatushaving one example of the embodiment of the releasing apparatus of thework having the adhesive tape will be explained.

First, the robot arm of the wafer transport mechanism 3 sucks and holdsone wafer W from the cassette of the wafer supply section 2 and takesthe wafer W out and transports the same onto the alignment stage 5. Thesurface of the wafer W is corrected into a flat surface by the waferpressing mechanism 4 and in this state, the wafer W is sucked and held.The positioning of the wafer W is carried out based on the orientationflat of the wafer W or detection of a notch or the like. Then, when thesurface protecting tape 20 joined to the wafer W is an ultraviolet rayshardening type tape, the tape is irradiated with ultraviolet rays on thealignment stage 5.

The alignment stage 5 is moved to a position below the wafer chuck table7, the positioned wafer W is received and supplied while keeping theflat surface with respect to the wafer chuck table 7.

The ring frame 8 sucks, holds and takes out the laminated ring framesupply sections 9 one by one, and transports the same to an joiningposition of the dicing tape 11.

Here, the dicing tape 11 is joined and then, the dicing tape 11 is cuton the ring frame 8. After the cutting, the unnecessary dicing tape 11is wound, and the ring flame 8 to which the dicing tape 11 is joined isformed.

Thereafter, the ring frame 8 is moved upward, the wafer and the dicingtape joined to the ring frame 8 by the mount roller is joined (wafermount) from a lower end of the ring frame 8.

Next, in order to separate the surface protecting tape 20 on the waferW, the wafer mount frame 29 is transported to the separating table 19and is sucked and held. The wafer mount frame 29 is sucked and held bydischarging out the gas in the passage 28 formed in the holding table 31by means of the vacuum pump 34. The separating tape 21 is joined to thesurface protecting tape 20 which is joined to the wafer W, and theseparating tape 21 is separated, thereby separating the surfaceprotecting tape. After the surface protecting tape 20 on the wafer W isseparated, the gas is supplied in succession between the separatingtable 19 and the wafer mount frame 29 from the central portion of thewafer mount frame 29 toward the outside thereof by the gas supply means33. With this, the adhesion between the wafer mount frame 29 and theseparating table 19 is deteriorated to facilitate the releasingoperation of the wafer mount frame 29 from the separating table 19.Then, the wafer mount frames 29 are accommodated into the wafer mountframe collecting section 26 one by one.

The present invention has the above-described structure. If thepolishing operation of the back surface is completed, a surface of thedicing adhesive tape which was joined for cutting (dicing) is mountedand held on the holding member which sucks and holds the dicing adhesivetape surface. Then, the surface protecting tape of the semiconductorwafer surface is separated (mount separating operation). Then, thesemiconductor wafer to which dicing adhesive tape is joined, i.e., thework having an adhesive tape is released from the holding member made ofporous material which sucks and holds. At that time, the work having theadhesive tape is released from the holding member while supplying thegas to reduce the holding force of the holding member between the workhaving the adhesive tape and the holding member. With this, it ispossible to prevent the work such as the semiconductor wafer from beingdamaged.

When the work having the adhesive tape is to be released, the gas can besupplied in a state in which the work having the adhesive tape is vacuumsucked. By supplying the gas in the state in which the work having theadhesive tape is vacuum sucked, the holding force by the vacuum suctioncan be adjusted. With this, the holding force by the vacuum suction canbe adjusted depending upon the kinds of the adhesive tape and thus, itis possible to prevent the adhesive tape from being deformed when theadhesive tape is vacuum sucked. Further, even if the work is made ofthin and friable material, since it is not sucked with a holding forcemore than necessary when it is sucked and held, it is possible toprevent the wafer from being damaged.

Although the wafer is used as the work having an adhesive tape in theabove embodiment, the work having the adhesive tape is not limited tothe wafer only if it is held on the holding member formed of porousmaterial and if it has the adhesive tape.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof and,accordingly, reference should be made to the appended claims, ratherthan to the foregoing specification, as indicating the scope of theinvention.

1-12. (canceled)
 13. An apparatus for holding and releasing a work froma holding member which sucks and holds the work having an adhesive tape,the apparatus comprising: a holding table having the holding member formounting and holding the work having the adhesive tape, the holdingmember having a plurality of suction holes; suction means connected tooperate the holding member as to suck and hold the adhesive tape whilemaintaining the adhesive tape in surface-to-surface contact with theholding member, in order to suck and hold the work having the adhesivetape on the holding member; and gas supply means for supplying a gas ata predetermined pressure through the holding member to the adhesivetape; and a controller for controlling the operation of at least one ofthe gas supply means and the suction means in a manner such that the gassupply means supplies a gas at a predetermined pressure to the adhesivetape through the holding member for preventing the adhesive tape frombeing drawn into the plurality of suction holes in the holding member,while the adhesive tape is sucked and held by the holding member,wherein a discharging pipe in communication with the suction means and asupply pipe in communication with the gas supply means are eachconnected in communication with a passage formed in different positionsat a bottom of the holding table, and both of the passages are connectedin communication with a horizontal passage intermediately formedparallel to an upper surface of the holding table and the horizontalpassage is diverged into a plurality of passages towards the uppersurface of the holding table.
 14. The apparatus according to claim 13,wherein the controller includes a control section which switches overthe suction and holding of the work having the adhesive tape by thevacuum means and the supply of gas between the holding member and thework having the adhesive tape by the gas supply means.
 15. The apparatusaccording to claim 13, wherein the holding table commonly uses thedischarging flow path for sucking the work having the adhesive tape bythe vacuum means, and the flow path for supplying the gas by the gassupply means.
 16. The apparatus according to claim 13, wherein theholding table separately includes the discharging flow path for suckingthe work having the adhesive tape by the vacuum means, and the flow pathfor supplying the gas by the gas supply means.
 17. The apparatusaccording to claim 13, wherein the holding member is made of a porousmaterial.
 18. The apparatus according to claim 13, wherein a backsurface of the work having the adhesive tape is joined to the ring frameand the semiconductor wafer to integrally form the ring frame and thesemiconductor wafer.